From 052e79941a042e5be4feffa03b1fd60d93fb9e9a Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Mon, 25 Sep 2006 23:32:25 -0700 Subject: [PATCH] x86: make __FIXADDR_TOP variable to allow it to make space for a hypervisor Make __FIXADDR_TOP a variable, so that it can be set to not get in the way of address space a hypervisor may want to reserve. Original patch by Gerd Hoffmann Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Chris Wright Cc: Gerd Hoffmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/mm/pgtable.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'arch/i386/mm/pgtable.c') diff --git a/arch/i386/mm/pgtable.c b/arch/i386/mm/pgtable.c index a9f4910a22f8..10126e3f8174 100644 --- a/arch/i386/mm/pgtable.c +++ b/arch/i386/mm/pgtable.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -139,6 +140,12 @@ void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags) __flush_tlb_one(vaddr); } +static int fixmaps; +#ifndef CONFIG_COMPAT_VDSO +unsigned long __FIXADDR_TOP = 0xfffff000; +EXPORT_SYMBOL(__FIXADDR_TOP); +#endif + void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags) { unsigned long address = __fix_to_virt(idx); @@ -148,6 +155,25 @@ void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags) return; } set_pte_pfn(address, phys >> PAGE_SHIFT, flags); + fixmaps++; +} + +/** + * reserve_top_address - reserves a hole in the top of kernel address space + * @reserve - size of hole to reserve + * + * Can be used to relocate the fixmap area and poke a hole in the top + * of kernel address space to make room for a hypervisor. + */ +void reserve_top_address(unsigned long reserve) +{ + BUG_ON(fixmaps > 0); +#ifdef CONFIG_COMPAT_VDSO + BUG_ON(reserve != 0); +#else + __FIXADDR_TOP = -reserve - PAGE_SIZE; + __VMALLOC_RESERVE += reserve; +#endif } pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) -- cgit v1.2.3